This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-373565, filed Dec. 25, 2002, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a contact-type IC card without built-in batteries, and more particularly to an IC card to counter erroneous input by a legitimate user and illegal use by a third party, and also relates to a method and program for preventing illegal use of an IC card.
2. Description of the Related Art
In general, an IC card is used to record important data such as personal information. Therefore, it is necessary to prevent illegal use of the card by a third party if it is lost. To this end, before a general IC card can be used, identification is performed using a personal identification number (PIN) (hereinafter referred to as xe2x80x9cPIN identificationxe2x80x9d), to identify the legitimate owner (hereinafter referred to simply as the xe2x80x9cownerxe2x80x9d) of the card. PIN information is generally stored in the IC card, and the owner of the card inputs their PIN through a terminal into which the IC card has been inserted. After the inserted PIN has been compared with the PIN stored in the IC card, the comparison result is sent to the terminal (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2000-76402).
In the PIN scheme, a card cracker who has acquired another person""s IC card may guess and input the PIN of the owner of the card in order to impersonate the legitimate owner of the card. To thwart such PIN guessing, the process of locking an IC card when an incorrect PIN is input a predetermined number of times is now employed (this is called xe2x80x9cPIN lockingxe2x80x9d). In a PIN-locked IC card, no further PIN input is possible, so the card cannot be used any more. PIN locking can be done on the system side (including the above-mentioned terminal, a server connected to the terminal, etc.) or on the IC card side.
PIN locking is performed to thwart card crackers. However, the owner of an IC card may well input their PIN incorrectly, resulting in PIN locking. If this happens, it is necessary to access, for example, the system manager to release the locked state. However, this is troublesome and so reduces the convenience of the IC card.
If the PIN locking of an IC card is limited to a certain length of time, a legitimate user can reuse the card sooner or later without the trouble of accessing, for example, the system manager. However, an illegitimate user is still prevented from continuously attempting to guess the PIN. So, there is a demand for setting a locking period.
However, if PIN locking is performed on the system side, it is necessary to centrally manage locking management information used for managing PIN locking, utilizing a server that handles a great many system-side terminals, and to access the locking management information each time PIN identification is performed. This increases the load on the system.
In light of the above, there is a need for a scheme in which PIN locking is performed on the IC card side. However, IC cards alone cannot provide their own power and so cannot time a PIN locking period. And if IC cards with built-in batteries are made, they lose the advantage of being usable without batteries.
The present invention has been developed in light of the above, and aims to provide an IC card capable of realizing PIN locking for a predetermined period without external power and without increasing the load on the system side including a terminal, server, etc., and also to provide a method and program for preventing illegal use of an IC card.
According to a first aspect of the invention, there is provided an IC card receiving a power from an external terminal and performing a process, the IC card comprising: a storage which stores first identification information uniquely assigned to the IC card; an acquisition unit configured to acquire second identification information from the external terminal; a first timer including a first change unit whose state changes with lapse of time without the power, the state of the first change unit changing from a first initial state to a final state via an intermediate state, the first timer outputting a first signal indicative of a changed state of the first change unit in response to an instruction issued when the IC card receives the power; a comparison unit configured to compare the second identification information with the first identification information, determine whether or not the second identification information and the first identification information are identical to each other, and provide a first initializing signal according to at least one of determined results; and a controller which initializes the first change unit to the first initial state when receiving the first initializing signal from the comparison unit, the controller further controlling the IC card to make it inhibit the process until the state of the first change unit changes to the intermediate state.
According to a second aspect of the invention, there is provided a method of preventing illegal use of an IC card, the IC card receiving a power from an external terminal and performing a process, the method comprising: preparing an IC card including a storage which stores first identification information uniquely assigned to the IC card, an acquisition unit configured to acquire second identification information from the external terminal, a first timer including a first change unit whose state changes with lapse of time without the power, the state of the first change unit changing from a first initial state to a final state via an intermediate state, the first timer outputting a first signal indicative of a changed state of the first change unit in response to an instruction issued when the IC card receives the power; comparing the second identification information with the first identification information, determining whether or not the second identification information and the first identification information are identical to each other, and providing a first initializing signal according to at least one of determined results; and initializing the first change unit to the first initial state when the first initializing signal is received, and inhibiting the process until the state of the first change unit changes to the intermediate state.
According to a third aspect of the invention, there is provided a program stored in a storage medium and executed by a processor included in an IC card, the program comprising: means for instructing a processor to compare second identification information with first identification information, determine whether or not the second identification information and the first identification information are identical to each other, and providing a first initializing signal according to at least one of determined results the IC card receiving a power from an external terminal and performing a process using the program, the IC card including: a storage which stores the first identification information uniquely assigned to the IC card; an acquisition unit configured to acquire the second identification information from the external terminal; and a first timer including a first change unit whose state changes with lapse of time without the power, the state of the first change unit changing from a first initial state to a final state via an intermediate state, the first timer outputting a first signal indicative of a changed state of the first change unit in response to an instruction issued when the IC card receives the power; and means for instructing the processor to initialize the first change unit to the first initial state when the first initializing signal is received, and instructing the processor to inhibit the process until the state of the first change unit changes to the intermediate state.